Treatment of tall oil



Patented May 21,1946

TREATMENT OF TALL OIL Ernest Segessemann, Newark, N. J., assignor toNational Oil Products Company, Harrison, N. J a corporation of NewJersey No Drawing. Application January 1, 1942,

Serial No. 425,347

19 Claims. (01. 260-975) This invention relates in general to'theproduction of valuable products from tall oil, and

more particularly to a process of separating tall' oil into its mainconstituents; i. e. fatty and resinic substances. The present inventionis especially directed 'to the recovery of valuable products from talloil in the course of which recovery the tall oil is subjected to bothhydrogenation and esterification, my copending application Serial No.309,703, now Patent No. 2,305,498, of which this is a continuation inpart being directed to a similar process during which the tall oil issubjected to hydrogenation to varying extents without being subjected toany extensive esterification; my .copending application Serial No.425,348, filed herewith, now Patent No. 2,373,979, being directed to asimilar process in which the tall oil is esterified to varying extentswithout being subjected to any extensive hydrogenation; and my copendingapplication Serial No. 425,346, filed herewith, now Patent No.2,373,978, being directed'to similar processes in which the tall oil'isneither esterified'nor hydrogenated to any considerable extent.

Tall oil" or talloel," which literally means pine oil, is the resinousand fatty'by-product obtained chiefly in the production of paper pulpfrom resin-bearing woods by the so-called sulphate process. In thesulphate process wood is digested with an alkaline .liquor containingsodium sulphate,- during which process tall oil accumulates in the formof its sodium soap on .the surface of the waste liquor. The mainconstitu- ..ents of this oil, after acidification, comprise resinicacids and fatty acids, the latter consistlng mainly of oleic, linoleic,and linolenic acids, each of which are valuable commodities insubstantially pure form. Various processes have been proposed in anattempt to effect separation of tall oil into its main constituents, i.e.,

One process comfatty acids and resinic acids. prises esterifying thefatty acids in tall oil with a low boiling alcohol and separating theresulting fatty ester from the free rosin acids by distillatlon or byalkali extraction. Another known process comprises esterifying the fattyacids with and other known processes have been employed with varyingdegrees of success, they all exhibit certain disadvantages, primarily inthat only drying properties, but these drying properties.

partial separation is effected. Moreover, the fatty acid fractionobtained by these processes, consisting mainly of a mixture of oleic,linoleic and linolenic acids, is not particularly suitable for a widevariety of industrialuses. Usually having an iodine value of about 120to 130, this fatty acid fraction (or its esters) shows some are notpronounced enough for adrying oil of good quality. On the other hand,this fatty acid fraction is too highly unsaturated to find extensiveapplication in some of the largest fat-consuming industries, namely thesoap industry, or in the manufacture of specialties for the textile andtanning trades, the bulk of fats used in I these industries being ofmore highly saturated type.

The general object of this invention is to obviate the foregoing andother disadvantages, A specific object of the invention is to provide animproved and more efiicient process for separating tall oil into itsmain constituents.

A further object of the invention is to provide an improved process forseparating tall oil into its constituents and recovering the fattyconstituents thereof in a more saturated form -so that the same can beadapted to a wide industrial use.

Still another object is to recover from tall oil a more highlyunsaturated fraction suitable for many technical applications.

Other objects will in partbe obvious and will in part appear hereafter.

'I'heforegoin and other objects are accomplished according to thebroader aspects of the invention whereby tall oil is treated withesterifying agents to convert the fatty acids therein to the form ofesters, and is further subjected to hydrogenation to decreasethe-unsaturation of the fatty materials. The esterifled and hydrogenatedtall oil is dissolved in a suitable solvent and subiected totemperatures sufliciently low to effect precipitation of a certainfraction of, or all of,

. the fatty esters thereof, followed by removal-of According to anotherprocess, both the said precipitated fraction by filtration orcentrifugation or by any other lmown 'means of separating'an insolublesolid from a liquid. The resinic constituents remaining in the solventmay be recovered by distilling off the solvent. The tall 011 estersemployed in accordance with the'process of the invention may be derivedfrom either crude or distilled tall oil and they may be subjected tovarying degrees of hydrogenation before being subjected to the chillingand separating steps. It the esterlfied tall oil used in the abovementioned process is of the crude or distilled type and has not beensubjected to very extensive h'y-' dro'genation, the filtrate obtainedupon separation of the precipitated fatty acids will also contain fattyesters of the more highly unsaturated type, mostly linoleic andlinolenic acids. These higher unsaturated fatty acids may then beseparated from the rosin by esterification followed by alkali have beenconverted to the oleic compounds, the

fatty fraction can be completely separated from the resinic substancesby cooling and filtration alone. A lesser degree of hydrogenation willresuit in a somewhat diminished yield of esters, the more unsaturatedesters tending to remain in,

solution. r

temperatures. Examples of such solvents include, inter alia, petroleumhydrocarbons, such as,

gasoline, kerosene, heptane, mineral spirits, etc.;

aromatic hydrocarbons, such as, benzene, toluene,

xylene, etc.; alcohols, such as ethylv alcohol,

methyl alcohol, isopropyl alcohol, etc.; ketones, such as acetone, ethylmethyl ketone, cyclohexanone, etc.; chlorinated hydrocarbons'such as,

ethylene dichloride, trichlorethylene, etc.

The steps of esterifying, hydrogenating and. dissolving the tall oil inthe solvent have been described above as following each other in thatsequence. Obviously, these steps may be carried out in any othersequence; the dissolving of the tall oil in the solvent may precede theesteriflcation and hydrogenation steps, the hydrogenation may precedethe other two steps,-and so on in the various possible permutations,these steps being additive and resulting in a solution of esterified andhydrogenated tall oil in the solvent,

which solution may be chilled to recover the de- 7 sired esters.Accordingly in the specification and This invention accordinglycomprises the several steps and the relation of one or more of suchsteps with respect to each of the others thereof, which will beexemplified in the process hereinafter disclosed, and the scope of theinvention will be indicated in the claims.

In carrying out the process of the invention, the first step involvesthe treatment of tall oil to convert the fatty acids therein-to the formof esters. Preferably the fatty acids are converted to esters ofmonohydric alcohols, rather than polyhydric, since otherwise mixed fattyand rosin v esters may be formed and a less sharp separation of thefatty from the resinic constituents may result. Preferably also, forbest results, the alcoholic constituents introduced by esterificationshould be derived from the lower alcohols containing from 1 to 5 carbonatoms. The esterification may be carried out to varying extents; forinstance, only the fatty acids in the tall oil may be converted to theform of esters, or, alternatively, a greater or lesser proportion of therosin acids may likewise be esterified. Any suitable esterificationreagents and processes may be employed, for instance refluxing the talloil with an appropriate alcohol in the presence of an esterificationcatalyst, or treating the tall oil at high temperatures and pressureswith an alcohol.

After the esterification step, the tall oil fatty esters are subjectedto partial or complete hydrogenation, depending on the type of fattyproducts desired. For example, partial hydrogenation of the fatty estersmay be carried on to convert a greater or lesser proportion of thelincleic and linolenic esters to oleic esters, whereby these esters willconstitute a large portion of, or substantially all oil, the fattyesters. On the other hand hydrogenation may be carried on further todecrease the degree of unsaturation in the resulting fatty esters,whereby all or substantially all the fatty esters will be converted intostearic at low temperatures and permitting the fatty acid derivativesthereof to precipitate out at low claims to follow, it is to beunderstood that the recitation in any order of these steps is to beconstrued to mean the combination of these steps indifferently in anyorder, unless thecontrary is explicitly indicated.

After there has been obtained the desired solution of the esterified andhydrogenated tall oil in a suitable solvent, the temperature of thesolution is decreased to obtain the desired degree of precipitation of.fatty esters thereof. By actual experiment, a temperature range ofabout 5 C. to 70 C. will accomplish this result. It is obvious, ofcourse, that temperatures outside of this" range may also be operativeto carry out the objects of the invention. ,The degree of cooling willbe varied according to the nature of the solvent used and according tothe form in which the fatty and resinous materials occur.- The degree ofcooling will be further varied according to the product desired, lowertemperatures being required when it is desired to remove a larger proportion of the esters from the solution. Moreover, the degree ofhydrcgenation'of the tall oil constituents will play an important rolein determining the time and temperature under which precipitation willbe eiiected. The precipitated fatty esters are removed from the solventsolution by any suitable means including centrifugation and filtration.The precipitated products after removal are preferably washed with asuitable solvent, i. e. the same solvent as used' in the process, andpreferably at substantially the same temperatureat which theprecipitating operation was carried out.

For. a fuller understanding of the nature and objects of the invention,reference should be had to the following examples, which are givenmerely to illustrate the invention and are not to be con strued in alimiting sense.

Example I The fatty acids in ice ems. of distilled tall oil 2 hours at apressure of atmospheres and at a temperature of C. in the presence of 3%of nickel as a catalyst.

100 gms. of the hydrogenated product which 'in a limiting sense.

had an iodine value of 25.4 were dissolved in 750 ml. of acetone andcooled at '-18"- C. overnight. The precipitated esters of the fattyacids were then filtered oil. and washed four times each. with 70 m1.portions of acetone cooled to 18 C. The

filter cake consisting of the methyl esters of the fatty acids was apure white solid below room temperature and upon analysis'it showed arosin content of .32% and an iodine value of 9.7%.

The rosin was then recovered from the filtrate by distilling off theacetone.

Example II oil in the presence of a solvent so as to effect a separationthereof into a fatty ester fraction 100 gms. of the methyl esters oftall oil, which Example III In a closed vessel which was provided with areflux condenser, 100 ms. of distilled tall oil having a rosin contentof 35% were heated with 11 gms. of anhydrous glycerol at such a ratethat the temperature rose gradually to 280 C. during six hours. Thetriglyceride of' tall oil thus obtained (having an acid value of 3.0)was then hydrogenated at a pressure of 7 atmospheres and at atemperature of 150 C. to 160 C. using 2% of nickel as a catalyst. Thehydrogenated prodnot had an iodine value of 46.0.

100 gms. of the hydrogenated product were dissolved in 700 ml. ofgasoline and cooled to 5 C. for 6 hours. The solid fraction was removedby filtration and washed with fresh gasoline. The product thus obtainedwas a white solid containing 18.5% of combined rosin.

Upon distillation of the gasoline from the ill-- trate, a heavy viscousfluid was obtained consisting of mixed triglycerides high in combinedrosin content. v

Since certain changes may be made in carrying out the above processwithout departing from the scope of the invention, it is intended thatall matter contained in the above description shall be interpreted asillustrative and not It is also to be understood that the followingclaims are intended to cover, all the generic and specific features ofthe invention herein described, and all statements of the scope of theinvention, which as a matter of language might be said to falltherebetween.

Having described my invention, what I claimas new and desire to secureby Letters Patent is: 1. A process of treating tall oil to separate afatty fractiontherefrom which comprises esterifying the fatty acids intall oil with a monohydric alcohol, hydrogenating the fatty acid estersin the esterified mixture, decreasing the' temperature of the resultingmass in the presence of a solvent to effect precipitation of fatty acidesters and removing the precipitated fatty acid esters from theremaining solution.

2. Process for treating tall oil which comprises, in indifferent order,hydrogenating the fatty insoluble in said solvent at the loweredtemperature and a solution of constituents soluble in said solvent atthe lowered temperature; and lastly separating the insoluble fatty esterfraction from said solution. V

3. Process for treating tall oil which comprises, in indifferent order,hydrogenating the fatty radicals in said oil and esterifying the samewith a monohydric alcohol; thereafter lowering the temperature of theesterified and hydrogenated tall oil in the presence of a solvent'soasto effect a. separation thereof into a fatty ester fraction insoluble insaid solvent at the lowered temperature and a solution of constituentssolable in said solvent at the lowered temperature;

and lastly separating the insoluble fatty ester fraction from saidsolution.

4. Process for treating tall oil' which comprises, in indifferent order,hydrogenating the fatty radicals in said 011 and esterifying the samewith methanol; thereafter lowering the temperature of the esterified andhydrogenated tall oil in the presence of a solvent so as to effect aseparation thereof into a fattyester fraction insoluble in said solventat the loweredtemperature and a solution of constituents soluble in saidsolvent at the lowered temperature; and

lastly separating the insoluble fatty ester fraction from said solution.v

5. Process for treating tall oil which comprises,

in indifferent order, hydrogenating the fatty radicals in said oil andesterifying the same with a, polyhydric alcohol; thereafter lowering thetemperature of the esterified and hydrogenated tall oil in the presenceof a solvent so as to effect a separation thereof into a fatty esterfraction insoluble in said solvent at the lowered temperature and asolution of constituents soluble in glycerol; thereafter loweringthetemperature of the esterified and hydrogenated tall oil in thepresence of a solvent so as to effects. separation thereof into a fattyester fraction insoluble in said solvent at the lowered temperature anda solution of constituents soluble in said solvent at the loweredtemperature; and lastly separating the insoluble fatty ester fractionfrom said solution.

7. Process for treating tall oil which comprises, in indifferent order,hydrogenating the fatty radicals in said oil to convert; them at leastto the oleic and esterifying the same with a lower a1-' cohol;thereafter lowering the temperature of the esterified andhydrogenatedtall oil in the 7 presence of a solvent so as to effect a separationthereof into a fatty ester fraction insoluble in said solvent at thelowered temperature and a solution of constituents soluble in saidsolvent at the lowered temperature; and lastly separating the insolublefatty ester fraction from said solution.

8. Process for treating tall oil which comprises,

in indifferent order, hydrogenating the fatty radradicals in said oiland esterifying the same with icals in said oil to convertthem at leastto the oleic and esterifying the same with a monoh'ydric. alcohol;thereafter lowering the tempera- 'perature of the esterified andhydrogenated tall ture of the esterified and hydrogenated tall-oil tionfrom said solution.

in the presence of a solvent so as to effect a separation thereof into afatty ester fraction insoluble in said solvent at the loweredtemperature and a solution of constituents soluble in said solvent atthelowered temperature; and lastly separating the insoluble fatty esterfrac- 9. Process for treating in. indifferent order, hydrogenating thefatty radicals in said oil to convert them at least to the oleic andesterifying the same with methanol; thereafter lowering the temperatureof the esterified and hydrogenated tall oil in the presence of a solventso as to'eifect a separation thereof into a fatty ester fractioninsoluble in said solvent at the lowered temperature and a solution ofconstituents soluble in said solvent at the lowered temperature; andlastly separating the insoluble fatty ester fraction from said solution.

10. Process for treating tall oil which comprises, in indifferent order,hydrogenating the fatty radicals in said oil to convert them at'least tothe oleic and esterifying the same with a polyhydric alcohol; thereafterlowering the temperature of the 'esterified and hydrogenated tall oil inthe presence of a solvent so as to efiect a separation thereof into afatty ester fraction insoluble in said solvent at the loweredtemperature and a solution of constituents soluble in said solvent atthe lowered temperature; and lastly separating the insoluble fatty esterfraction from said solution.

ing the insoluble fatty ester fraction from said solution.

1.2. Process for treating tall oil whichv com- I prises; inindifferentorder, hydrogenating the fatty radicals .in said 011' and esterifyingthe same with a lower alcohol; thereafter lowering the temperature ofthe esterified and hydrogenated tall oil in the presence of acetone soas 'to effect a separation thereof into a fatty ester fraction insolublein said solvent at the lowered 1 tall' oil in the presence of ethylenedichloride. 'so'as to effect a separationthereof into a fatty esterfraction insoluble in said solvent at the lowered temperature andasolution of constituents soluble in said solvent-at the loweredtemperature; and lastly separating. the insoluble fatty ester fractionfroinsaid solution.

14. Process for treating tall oil which comprises, in indifferent order,hydrogenating. the

fatty radicals in said tall 011- and esterifying the a tall oil whichcomprises,

tall oil which com-- 2,400,607 a; d J same with a lower alcohol;thereafter lowering the temperature of the esterified and hydrogenatedtall oil in the presence of a petroleum fraction so as to effect aseparation thereof into 5 a fatty ester fraction insoluble in saidsolvent at the lowered temperature and a solution of constituentssoluble in said solvent at the lowered temperature; and lastlyseparating the insoluble fatty ester fraction from said solution.

15. Process for treating tall 011 which comprises, in indifferent order,hydrogenating the fatty radicals in said oil to reduce the iodine valueof the oil below about 1 0 and es'terifying the same with a loweralcohol; thereafter lowering the temperature of the esterified andhydrogenated tall oil in the presence of a solvent so as to effect aseparation thereof into a fatty ester fraction insoluble in said solventat the lowered temperature and a solution of constituents soluble insaid "solvent at'the lowered temperature; and lastly separating theinsoluble fatty ester fraction from said solution.

16. Process for treating tall oil which; comprises, in indifferentorder, hydrogenating the fatty radicals in said oil to reduce the iodinevalue thereof below about 10 and esterifying the same with a monohydricalcohol; thereafter lowering the temperature of the esterified andhydrogenated tall oil in the presence of a solvent so as to efiect aseparation thereof into a fatty ester fraction insoluble in said solventat the lowered temperature and a solution of constituents soluble insaid solvent at the lowered temperature; and lastly separating theinsoluble fatty ester fraction from said solution. l7.-Process fortreating tall oil which comprises, in indifferent order, hydrogenatingthe fatty radicals in said tall oil and esterifying the same with alower alcohol; thereafter dissolving 40 the hydrogenated and esterifledtall oil in'a solvent therefor; lowering the temperature of theresultant solution so as to eifect a separation thereof into a fattyester fraction insoluble in said solvent at the lowered temperature anda" solution of. constituents soluble in said solvent at the loweredtemperature; and lastly separat,-'

ing the insoluble fatty ester fraction from said solution. 1

18. Process for treating tall oil which comprises, in'indifferent'order, hydrogenating the fatty radicals in said oil and esterifyingthesame with a monohydric alcohol; thereafter, dissolving thehydrogenated and esterifled tall oil in'a solvent; lowering thetemperature of the resultant solution so as to effect a separationthereof into a fatty ester fraction insoluble in said solvent at thelowered temperature and a solution of constituents soluble in saidsolvent 1 at the lowered temperature; and separating the insoluble fattyester fraction from said solution.

19. Process for treating tall oil which comprises, in'indifl'erentorder, hydrogenating the fatty radicals in said tall oil'and'esterifying the -same withfla polyhydricalcohol; thereafterdissolving the hydrogenated and esteriiled tall oil .in a solventtherefor; lowering the temperature of the resultant solutionso as toeflect a separation thereof into a fatty ester fraction insoluble insaid solvent at the lowered tempera- 7 ture and a solution ofconstituents soluble in said solvent at the lowered temperature; andseparating the insoluble fatty ester fraction from *saidsolution. l o vI .ERNEST SEGESSEMANN.

